Method for controlling antennas of mobile terminal device and such a mobile terminal device

ABSTRACT

A method for controlling antennas of a mobile terminal device such as a laptop PC and a handheld PC without degrading communication speed or quality and a mobile terminal device having such control means are provided. The method comprises determining the usage of the mobile terminal device, determining an antenna to be disabled among the plurality of antennas according to the usage that is determined by the determining of usage, and disabling the antenna disabling of which is determined by determining of an antenna to be disabled, wherein the determining of usage determines usage based on the display orientation of the display unit of the mobile terminal device.

CLAIM FOR PRIORITY

This application claims priority from Japanese Patent Application No.2005-164280, filed Jun. 3, 2005, and which is hereby incorporated byreference as if fully set forth herein.

BACKGROUND OF THE INVENTION

The present invention relates to a method for controlling the antennasof a mobile terminal device that has a plurality of antennas, forexample. More particularly, the present invention relates to a methodfor controlling antennas in accordance with the usage of such a mobileterminal device and to such a mobile terminal device.

In recent years, the effects of electromagnetic wave emitted from mobileterminal devices on the human body has been a subject of considerableinterest, and technologies for reducing absorption of electromagneticwave into the human body have become an issue in designing mobileterminal devices. For example, in the United States, a standard has beenestablished that prescribes the acceptable value of Specific AbsorptionRate (SAR), which is a measure of electric energy of electromagneticwave absorbed by the human body, to be under 1.6 W/kg.

In such a circumstance, for a mobile terminal device that has aplurality of antennas for wireless communication, a method has beenproposed for always selecting an antenna with better SAR properties foruse from the plurality of antenna on such a device. For example,Japanese Unexamined Patent Publication No. 2003-283393 discloses amethod for switching between “a first antenna that is designed to obtainpreferable SAR properties in all usages” and “a second antenna that isnot so designed” and using the selected one in accordance with how amobile terminal device (e.g., a mobile phone) is being used for thepurpose of reducing SAR associated with a mobile terminal device.

Specifically, the method switches between the first antenna and thesecond antenna according to the usage of the mobile terminal device,such as whether the external data terminal is in use or not, whetherhandsfree communication is being carried out or not, whether or not theexternal audio communication terminal is in use, whether the camera isin use or not, whether image communication is being carried out, orwhether packet communication is being carried out. In addition, atechnique that is based on a method for determining the distance betweenthe mobile terminal device and the human body and a technique based on amethod for detecting opening/closing of the housing of the mobileterminal device have been also disclosed. Thus, the method disclosed byJapanese Unexamined Patent Publication No. 2003-283393 is intended toimprove SAR properties while avoiding degradation of communication speedand quality of a mobile terminal device as much as possible.

However, another issue arises when such a method is applied to a laptopPC or handheld PC, for example.

More specifically, a mobile phone can have various usages, that is, amobile phone may be used as a data communication terminal, audiocommunication terminal, camera, image communication terminal, packetcommunication terminal and so on as mentioned above. Thus, it isnecessary to employ a complex control method such as the one describedabove to select an antenna according to such usages. In addition, such adevice has to be small in size for use as a mobile phone. For thosereasons, even if a terminal has a plurality of antennas, when theterminal is used in close contact with the human body such as for voicecall, it could be difficult to reduce SAR unless, transmission outputitself is reduced for any antenna at any position selected. Thus, insuch a case, with the method disclosed by Japanese Unexamined PatentPublication No. 2003-283393, it is necessary to select an antenna thatis designed to limit transmission output in order to maintain preferableSAR properties. In this case, degradation of communication speed andquality of the mobile phone has to be accepted.

On the other hand, a laptop PC or handheld PC does not have so manyusages as a mobile phone. In addition, size of such mobile terminaldevices for use as a terminal is less restricted. With these features,control could become too complex if the antenna control method for amobile phone terminal device described above is applied to a laptop PCor a handheld PC without modification. To realize such complex control,many devices such as sensors are required for detecting how the terminaldevice is used. As a result, the mechanism of a mobile terminal deviceitself becomes complex and there would be more causes of troubleaccordingly. In addition, when an antenna with its output limited low isselected, communication speed or quality of the mobile terminal devicedegrades.

In view of such circumstances, it is desirable to provide a method forcontrolling antennas without degrading communication speed or quality ofa mobile terminal device such as a laptop PC and a handheld PC as wellas a mobile terminal device having such control means.

SUMMARY OF THE INVENTION

The present invention provides a method for controlling a plurality ofantennas of a mobile terminal device, comprising determining the usageof the mobile terminal device, determining an antenna to be disabledamong the plurality of antennas according to the usage that isdetermined by the determination of usage, and disabling the antennadisabling of which is determined by determination of an antenna to bedisabled, wherein the determining of usage determines usage based on thedisplay orientation of the display unit of the mobile terminal device.

Alternatively, the determining of usage determines usage based on theorientation of holding the mobile terminal device that is detected by aholding orientation sensing unit of the mobile terminal device.

Alternatively, the determining of usage determines usage based oninstallation status detected by an installation status sensing unit ofthe mobile terminal device.

According to the invention, an antenna to be disabled is determined asappropriate from among a plurality of antennas provided in accordancewith the usage of a mobile terminal device. The usage of the mobileterminal device is determined based on display orientation on thedisplay unit, the orientation of holding the device, and combination ofthem and installation status. The output of the plurality of antennasprovided need not be necessarily reduced. The method according to theinvention controls antennas of a laptop PC or a handheld PCappropriately, for example.

According to the method of the invention, antennas of a mobile terminaldevice can be controlled so as to reduce SAR on the human body withoutdegrading communication speed or quality. For example, the method cancontrol SAR adequately on a laptop PC or a handheld PC among others.

For a better understanding of the present invention, together with otherand further features and advantages thereof, reference is made to thefollowing description, taken in conjunction with the accompanyingdrawings, and the scope of the invention will be pointed out in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 generally illustrates a physical configuration of a mobileterminal device 1 according to an example of a preferred embodiment ofthe invention;

FIG. 2 illustrates movement of a housing of the mobile terminal device 1according to an example of the preferred embodiment of the invention;

FIG. 3 illustrates movement of a housing of the mobile terminal device 1according to an example of the preferred embodiment of the invention;

FIG. 4 illustrates movement of a housing of the mobile terminal device 1according to an example of the preferred embodiment of the invention;

FIG. 5 illustrates the relation between the display orientation of thedisplay unit 11 and antenna control of the mobile terminal device 1according to an example of the preferred embodiment of the invention;

FIG. 6 illustrates the relation between the display orientation of thedisplay unit 11 and antenna control of the mobile terminal device 1according to an example of the preferred embodiment of the invention;

FIG. 7 illustrates the relation between the display orientation of thedisplay unit 11 and antenna control of the mobile terminal device 1according to an example of the preferred embodiment of the invention;

FIG. 8 illustrates the relation between the display orientation of thedisplay unit 11 and antenna control of the mobile terminal device 1according to an example of the preferred embodiment of the invention;

FIG. 9 shows a hardware configuration of the mobile terminal device 1according to an example of the preferred embodiment of the invention;

FIG. 10 shows a functional configuration of the mobile terminal device 1according to an example of the preferred embodiment of the invention;

FIG. 11 shows a functional configuration of the mobile terminal device 1according to another example of the preferred embodiment of theinvention;

FIG. 12 is a flow diagram illustrating the flow of antenna controlaccording to an example of the preferred embodiment of the invention;

FIG. 13 is a flow diagram illustrating the flow of antenna controlaccording to an example of the preferred embodiment of the invention;and

FIG. 14 is a flow diagram illustrating the flow of antenna controlaccording to an example of the preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

A preferred embodiment of the present invention will be described withrespect to drawings.

FIG. 1 generally illustrates a configuration of a mobile terminal device1 according to an example of a preferred embodiment of the invention.The mobile terminal device 1 has two housings 14 and 15 that areapproximately rectangular parallelpipeds. The housing 14 has an inputunit 10, and the housing 15 has a display unit 11. Further, the housings14 and 15 are connected by a joint unit 13 at a point at the center oftheir edge, and can be moved in the direction of opening/closing thehousings. The housing 15 can be rotated at least 180° with the housing15 perpendicular to the housing 14. Thus, the mobile terminal device 1may be used as a usual laptop PC as shown in FIG. 1, or as a handheld PCthat has a touch panel input unit 16 and the like by rotating thehousing 15 at the joint unit 13 as shown in FIG. 2 and folding thehousing 15 with the display unit onto the housing 14 that has the inputunit 10 as illustrated in FIGS. 3 and 4.

Here, a laptop PC is not limited to such one shown in FIG. 1, but it maybe a so-called portable personal computer that has parts such as a CPU,memory, hard disk device, keyboard, display panel and the like. Also, ahandheld PC is not limited to such one shown in FIG. 4, but it may be aso-called portable computer or an information processing terminal thatalso has a CPU, memory, hard disk device, touch panel, pen input panelor display panel as input means. Further, devices falling withincategories called electronic organizer or PDA may be also included.Also, the terminal device may include a keyboard as input means.

As shown in FIG. 5, the mobile terminal device 1 has a first antenna 100and a second antenna 110 on each of two sides of the housing 15 thatsupports the display unit 11. These antennas are connected to a wirelessLAN card 120 and the antennas and the LAN card operate in cooperation torealize communication means of the mobile terminal device 1. The mobileterminal device 1 further includes a display orientation rotation button17 on the same surface as the display unit 11 of the housing thatsupports the display unit 11. By pressing the button 17, a user canchange the orientation of display on the display unit 11 by apredetermined angle, e.g., 90° and 180°. The display orientationrotation button 17 may be provided at any position on the housings ofthe mobile terminal device 1 as long as it may be operated both when theterminal device 1 is used as a laptop PC (FIG. 1, for example) and as ahandheld PC (FIG. 4, for example).

Further, the display orientation of the display unit 11 may beautomatically changed based on the difference in positional relationshipof the two housings for the case the terminal is used as a laptop PC asshown in FIG. 1 and the case it is used as a handheld PC as shown inFIG. 4.

FIG. 5 illustrates the display orientation of the mobile terminal device1 in a first portrait display mode. In an example of the preferredembodiment of the invention, in this display mode, it is determined thatthe second antenna 110 that is positioned lower relative to the displayorientation is closer to the user's body, and the second antenna 110 isdisabled in consideration of the way the user holds the terminal device1.

FIG. 6 illustrates the display orientation of the mobile terminal device1 in a second portrait display mode. The display orientation in thismode is shifted 180° from the first portrait display mode shown in FIG.5. The user of the mobile terminal device 1 can switch between thesedisplay modes by pressing the display orientation rotation button 17. Inan example of the preferred embodiment of the invention, in this displaymode, it is determined that both the first antenna 100 and secondantenna 110 are away from the user's body and both the antennas areenabled considering the way the user holds the terminal device 1. Inthis case, an antenna with better use conditions is selected for use bya known method conventionally employed.

Further, as illustrated in FIG. 7, in a first landscape display mode ofthe mobile terminal device 1, the first antenna 100 positioned lowerrelative to the display orientation is considered to be closer to theuser's body considering how the user holds the terminal device 1, andthe first antenna 100 is disabled. When in a second landscape displaymode of the mobile terminal device 1 as shown in FIG. 8, it isdetermined that both the first antenna 100 and second antenna 110 areaway from the user's body considering how the user holds the terminaldevice 1, and both the antennas are enabled. In this case, an antennawith better use conditions is selected for use by a known methodconventionally employed.

Thus, according to the invention, an antenna positioned lower relativeto display orientation is considered to be closer to the user's body andcan be automatically disabled taking into consideration how the userholds the terminal. Consequently, an antenna closer to the hand or bodyof the user holding the mobile terminal device I is disabled and only anantenna farther from the user's hand or body is enabled, so that SAR onthe human body can be minimized while the user can use wirelesscommunication all the time.

Alternatively, an acceleration sensor may be included in the housing ofthe mobile terminal device 1 and any of the four usages shown in FIGS.5-8 may be determined from the orientation of holding the terminal thatis detected by the acceleration sensor. Specifically, if an antennaexists on a side that is determined to be positioned downmost among thefour sides of the housing, it is determined that the antenna is closerto the user's body and is disabled. In this case, the determination canbe made without using information on the display orientation on thedisplay unit 11.

Further, the display orientation of the display unit may beautomatically changed according to the determination of the verticalrelationship of the housings. This allows the display orientation of thedisplay unit 11 to be changed and an antenna more suitable for thedisplay orientation to be selected without the user pressing the displayorientation rotation button 17 whenever the user changes the way ofholding the mobile terminal device 1.

Also, when the mobile terminal device 1 is connected to a dockingstation (i.e., used as a laptop PC), the connection may be detected by asensor, and both the first and second antennas 100 and 110 may beenabled regardless of the display orientation by the instruction for theterminal detected by an acceleration sensor. In this case, an antennawith better use conditions would be selected for use by a known methodconventionally employed.

FIG. 9 illustrates a hardware configuration of the mobile terminaldevice 1 of the invention. A control unit 140 controls the entire mobileterminal device 1. The mobile terminal device 1 also has a communicationcontrol unit 130 that includes an antenna control unit 131 forcontrolling the first and second antennas 100 and 110. The antennacontrol unit 131 determines an antenna to be disabled and stops the useof the antenna according to the determination as described earlier.

The mobile terminal device 1 may include an acceleration sensor 150. Themobile terminal device may also include a docking sensor 160 fordetecting whether the terminal device 1 is connected to a dockingstation. Using detection result by these sensors, the antenna controlunit 131 controls the antennas in cooperation with the control unit 140as mentioned above. These pieces of hardware are interconnected by a bus180. Programs stored in a storage unit 170 are read out and executed asnecessary by the control unit 140, causing the pieces of hardware tocooperate to realize the various means of the invention.

As can be readily appreciated by those skilled in the art, theacceleration sensor 150 is available in various mechanisms, such as onethat is combination of piezoelectric ceramic device and electrodes. Whenacceleration (gravitational acceleration in resting state, for example)is externally applied to the piezoelectric ceramic devices, thepiezoelectric ceramic devices distort to generate stress internally. Thestress is converted to electric signal (electric charge) withpiezoelectric effect and the direction and magnitude of the accelerationcan be detected from the electric signal. This allows the direction ofthe gravitational acceleration to be detected in resting state, and theorientation in which the mobile terminal device 1 is held can becalculated from the direction.

FIG. 10 illustrates a functional configuration of the mobile terminaldevice 1 according to an example of the preferred embodiment of theinvention. The control unit 140 controls the entire mobile terminaldevice 1. The control unit 140 provides various functions of the mobileterminal device 1 in conjunction with the antenna control unit 131 forcontrolling the first and second antennas 110 and 110, a built-in buttoncontroller 240 for controlling built-in buttons such as the displayorientation rotation button 17, and a graphic controller 250 forcontrolling the display unit 11. On an operating system (OS) 200,various user applications such as a word processor can run. The OS 200drives various pieces of hardware via the control unit 140, antennacontrol unit 131, built-in button controller 240, and graphic controller250 by way of kernel-level process groups that consist of a built-inbutton driver 220, a graphic driver 230 and the like.

In an example of the preferred embodiment of the invention, when theuser presses the display orientation rotation button 17 of the mobileterminal device 1, the built-in button controller 240 senses thepressing. The built-in button controller 240 then informs the OS 200 ofthe pressing via the built-in button driver 220. The OS 200 sends acommand for rotating the screen by a predetermined rotation angle (e.g.,90°) to the graphic controller 250 via the graphic driver 230. Thegraphic controller 250 receives the command and rotates the displayorientation of the display unit 11 (e.g., 90°) accordingly. Further,upon detecting the pressing of the display orientation rotation buttonvia the OS 200 and the like, the control unit 140 confirms the displayorientation of the display unit 11 to the OS 200. The OS 200 obtainsinformation on display orientation from the graphic controller 250 viathe graphic driver 230. The control unit 140 obtains the information ondisplay orientation from the OS 200, determines whether todisable/enable the first and/or second antennas based on the informationon display orientation, and executes the determination via the antennacontrol unit 131.

FIG. 11 illustrates a functional configuration of the mobile terminaldevice 1 according to another example of the preferred embodiment of theinvention. As in FIG. 10, the control unit 140 controls the entiremobile terminal device 1. The control unit 140 provides variousfunctions of the mobile terminal device 1 in conjunction with theantenna control unit 131 for controlling the first and second antennas100 and 110, a device controller 270 for controlling the accelerationsensor 150 and docking sensor 160, and a graphic controller 250 forcontrolling the display unit 11. On the operating system (OS) 200,various user applications such as a word processor can run. The OS 200drives various pieces of hardware via the control unit 140, antennacontrol unit 131, device controller 270, and graphic controller 250 orthe like, by way of kernel-level process groups that consist of thedevice driver 260 and graphic driver 230.

In another example of the preferred embodiment of the invention, whenthe user changes the orientation of holding the terminal, theacceleration sensor 150 detects the change. When the change in holdingorientation is detected, the change is informed to the OS 200 via thedevice driver 260. The control unit 140 is informed of the change by theOS 200, and based on the information on the change, determines whetherto disable/enable the first and/or second antennas and executes thedetermination via the antenna control unit 131.

Further, in yet another example of the preferred embodiment of theinvention, the docking sensor 160 senses the connection of the mobileterminal device 1 to a docking station (not shown). In this case, aswith the acceleration sensor 150, the control unit 140 recognizes theconnection and changes the display orientation of the display unit 11 tothe second landscape display mode shown in FIG. 8 via the graphiccontroller 250. Further, the control unit 140 enables both the first andsecond antennas via the antenna control unit 131. Here, an antenna withbetter use conditions is selected for use by a known methodconventionally employed.

FIG. 12 is a flow diagram illustrating the flow of antenna controlaccording to an example of the preferred embodiment of the invention.First, the control unit 140 determines whether or not the displayorientation rotation button 17 has been pressed (step S01). If itdetermines that the button has been pressed, the control unit 140queries the OS (operating system) running on the mobile terminal device1 about the display orientation of the display unit 11 (step S02).

If the query returns the first portrait display mode shown in FIG. 5(step S03), the antenna control unit 131 disables the second antenna 110(step S04). On the other hand, the query returns the second portraitdisplay mode shown in FIG. 6 (step S05), the antenna control unit 131enables both the first and second antennas 100 and 110 (step S06). Inthe latter case, an antenna with better use conditions is selected foruse by a known method conventionally employed.

If the query returns the first landscape display mode shown in FIG. 7(step S07), the antenna control unit 131 disables the first antenna 100(step S08). If the query returns the second landscape display mode shownin FIG. 8 (step S09), the antenna control unit 131 enables both thefirst and second antennas 100 and 110 (step S10). In the latter case, anantenna with better use conditions is selected for use by a known methodconventionally employed.

In this manner, control starting from step S01 is repeated until the useof the mobile terminal device ends (step S11).

FIG. 13 is a flow diagram illustrating the flow of antenna controlaccording to another example of the preferred embodiment of theinvention. First, the control unit 140 determines whether or not theholding orientation of the mobile terminal device 1 has changed (stepS101). Then, if the control unit 140 determines that the holdingorientation has changed and that the second side shown in FIG. 5 is atthe bottom (step S103), the antenna control unit 131 disables the secondantenna 110 (step S104). Meanwhile, if the control unit 140 determinesthat the holding orientation has changed and that the fourth side shownin FIG. 5 is at the bottom (step S105), the antenna control unit 131enables both the first and second antennas 100 and 110 (step S106). Inthe latter case, an antenna with better use conditions is selected foruse by a known method conventionally employed.

If the control unit 140 determines that the holding orientation haschanged and that the first side shown in FIG. 5 is at the bottom (stepS107), the antenna control unit 131 disables the first antenna 100 (stepS108). If the control unit 140 determines that the holding orientationhas changed and that the third side shown in FIG. 5 is at the bottom(step S109), the antenna control unit 131 enables both the first andsecond antennas 100 and 110 (step S110). In the latter case, an antennawith better use conditions is selected for use by a known methodconventionally used.

Control starting at step S101 is repeated in such a manner until the useof the mobile terminal device ends (step S111).

FIG. 14 is a flow diagram illustrating the flow of antenna controlaccording to yet another example of the preferred embodiment of theinvention. Initially, the control unit 140 determines whether or not themobile terminal device 1 has been connected to a docking station (stepS121). If the control unit 140 determines that the terminal is connectedto the docking station, the control unit 140 changes the displayorientation of the display unit 11 to the second landscape display modeof FIG. 8 (step S122), and the antenna control unit 131 enables both thefirst and second antennas 100 and 110 (step S123). Here, an antenna withbetter use conditions is selected for use by a known methodconventionally employed.

Control starting at step S121 is repeated in such a manner until use ofthe mobile terminal device ends (step S124).

Although the above embodiments describes a case where the mobileterminal device 1 has two antennas, if the terminal device has three ormore antennas, any antenna that is positioned lower relative to thedisplay orientation of the display unit can be disabled in the same way.Also, any antenna that is positioned downmost as determined by anacceleration sensor can be disabled in the same way as described above.

Also, although use of an antenna with its transmission output reduced isnot necessarily required in the preferred embodiment of the invention,the invention is not intended to deny the use of such an antenna. Forexample, it is also possible that the terminal device has more antennasand transmission output of some of the antennas is reduced.

If not otherwise stated herein, it is to be assumed that all patents,patent applications, patent publications and other publicationsmentioned and cited herein are hereby fully incorporated by referenceherein as if set forth in their entirety herein.

While the embodiment of the present invention has been described, thedescription only illustrates specific examples and does not limit theinvention particularly. Also, the operation mentioned in the embodimentof the invention only illustrates specific examples and the operationprovided by the present invention is not limited to that described inthe embodiment of the invention.

1. A method for controlling a plurality of antennas of a mobile terminaldevice, comprising: determining a usage of said mobile terminal device;determining an antenna to be disabled among said plurality of antennasaccording to the usage that is determined by said determining of usage;and disabling the antenna, disabling of which is determined by saiddetermination of an antenna to be disabled, wherein said determining ofusage determines usage based on a display orientation of a display unitof said mobile terminal device.
 2. The method according to claim 1,wherein said determining of usage determines usage based on installationstatus that is detected by an installation status sensing unit of saidmobile terminal device.
 3. The method according to claim 2, wherein saidmobile terminal device is a laptop PC or a handheld PC.
 4. A method forcontrolling a plurality of antennas of a mobile terminal device,comprising: determining a usage of said mobile terminal device;determining an antenna to be disabled among said plurality of antennasaccording to the usage that is determined by said determining of usage;and disabling the antenna, disabling of which is determined by saiddetermining of an antenna to be disabled, wherein said determining ofusage determines usage based on an orientation of holding said mobileterminal device that is detected by a holding orientation sensing unitof said mobile terminal device.
 5. A mobile terminal device having aplurality of antennas, comprising: usage determination means fordetermining a usage of said mobile terminal device; disablingdetermination means for determining an antenna to be disabled among saidplurality of antennas according to usage that is determined by saidusage determination means; and disabling means for disabling theantenna, disabling of which is determined by said disablingdetermination means, wherein said usage determination means determinesusage based on a display orientation of a display unit of said mobileterminal device.
 6. The mobile terminal device according to claim 5,wherein said usage determination means determines usage based oninstallation status that is detected by an installation status sensingunit of said mobile terminal device.
 7. The mobile terminal deviceaccording to claim 6, wherein said mobile terminal device is a laptop PCor a handheld PC.
 8. A mobile terminal device having a plurality ofantennas, comprising: usage determination means for determining a usageof said mobile terminal device; disabling determination means fordetermining an antenna to be disabled among said plurality of antennasaccording to usage that is determined by said usage determination means;and disabling means for disabling the antenna, disabling of which isdetermined by said disabling determination means, wherein said usagedetermination means determines usage based on an orientation of holdingsaid mobile terminal device that is detected by a holding orientationsensing unit of said mobile terminal device.